A magnet assembly has been utilized to generate a uniform magnetic field for magnetic resonance imagining (MRI) systems. During manufacture of the magnet assembly, a non-magnetized plate comprising a plurality of rare-earth blocks is disposed on an iron yoke wherein the non-magnetized plate is subsequently magnetized. To simultaneously magnetize the plurality of blocks, a relatively large magnetic coil is disposed over the non-magnetized blocks that propagate a large magnetic field through the blocks.
Utilization of the relatively large magnetic coil to magnetize the non-magnetized blocks, however, has several drawbacks. First, the large magnetic coil generates relatively large amounts of heat in the blocks of the magnetic assembly and in the coils themselves that must be cooled to maintain the structural integrity of the blocks and the coils. To cool the blocks, additional cooling systems must be disposed adjacent the magnetic coil which is relatively expensive. Second, the large magnetic coils require large amounts of electrical current to generate the large magnetic field that requires relatively expensive current drivers. Third, the large magnetic coil produces relatively large electromagnetic forces on the blocks and counterforces on the coils during magnetization. To maintain the blocks and the coils at desired positions, relatively large fixtures are clamped to the yoke plates that are relatively expensive.
There is thus a need for a process of magnetizing blocks on a magnet assembly used in an MRI system that overcomes one or more of the above-mentioned deficiencies.